I’d think it would be obvious that a country wouldn’t want to depend on a foreign country’s proprietary product when an open source alternative exists. Even if it’s not spying, what if the US forced Microsoft to put some kill switch on their products? Even if it doesn’t affect your most secure systems because of air gap, it could still cripple enough to cause huge problems.

There’s simply no reason to take the risk.

If I was running a government, I would strongly desire proof that all of my government software is doing only what I want it to. That means not only do I have access to the source code, but I also need it to be simple enough that my government teams can actually audit all of it.

Obviously, that’s not going to be feasible in every situation. There might be proprietary software that is protected from competition via IP laws, and some software is so necessarily complex that it would be really hard to audit completely, but overall, I find it shocking that any foreign government would run a Microsoft product when a feature comparable open source alternative exists.